This ivention relates to a belt type pickup mechanism that mounts on an auger type grain harvesting platform on a combine, and more particularly to an improved windrow hold-down device that controls the mat of crop material after it is raised from the ground and while it is being moved rearwardly on the upper run of the pickup belt.
A grain combine typically includes a transversely elongated header with a crop converging suger. When the combine is operating in a standing crop, the platform is provided with a cutting device along its leading edge for severing the crop material from the field. However, with certain crops and in certain areas, the standing crop is first cut and allowed to dry in the field, the crop being laid in windrows by a windrowing machine. In such a case, the combine is provided with a pickup mechanism at the front of the platform that raises the windrow of crop material from the ground as the machine advances and feeds it rearwardly to the crop converging auger on the combine platform. In many cases, the pickup mechanism utilizes a belt having a large number of outwardly extending fingers that engage the crop material and elevate it from the ground, the crop material then being conveyed rearwardly on the upper run of the belt to the platform auger. A machine of the above general type is disclosed in U.S. Pat. No. 3,474,605, which is also assigned to the assignee herein.
In such a machine, the pickup is supported relatively close to the ground by a pair of gauge wheels at opposite sides of the pickup mechanism. Since the gauge wheels roll along the ground, which frequently is quite rough and uneven, the frame of the pickup mechanism is designed so that it is flexible enough to accommodate vertical movement of one side of the frame relative to the other.
It is also conventional to provide a device known as a windrow hold-down or wind guard above the pickup belt to hold the mat of crop material down on the upper run of the belt so that it does not bunch up on the top of the belt in front of the auger, it being desirable that the crop material be fed under the front side of the auger in a mat of fairly consistent thickness. Typically, a windrow hold-down device comprises a number of fore-and-aft fingers that are mounted on and extend rearwardly in cantilever fashion from a transverse bar above the upper run of the pickup belt. The fingers normally engage the top of the mat of the crop material moving rearwardly along the upper run of the belt and prevent the formation of bunches of crop material on the top of the belt, the flexibility of the fingers allowing for some variation in the thickness of the mat of crop material. However, since crop conditions vary and there is a wide variation in the amount of crop material lying in a windrow, means are normally provided to adjust the clearance between the fingers in the top of the belt since the thickness of the windrows vary due to changes in the crop or crop conditions.
While the hold-down fingers have been adjustable, in the past they have been mounted on a bar that has its opposite ends rigidly attached to the opposite sides of the pickup mechanism frame. Since the opposite ends of the frames shift vertically relative to one another when operating on rough terrain, some distortion of the rigidly connected windrow hold-down structure occurs, which, in some severe cases, has resulted in failure of the structure. Also, while the rigidly mounted fingers are free to flex vertically to accommodate some variation in the thickness of the mat of crop material, when operating in extremely heavy windrow conditions, the fingers have not been able to flex far enough so that they do not restrict the flow of material to the platform.